EP2905469A1

EP2905469A1 - Hermetic scroll compressor

Info

Publication number: EP2905469A1
Application number: EP15151872.7A
Authority: EP
Inventors: Youhei Hotta; Yoshiyuki Kimata; Masahiro Taniguchi; Hajime Sato; Taichi Tateishi; Takao Ishimoto
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2014-02-06
Filing date: 2015-01-21
Publication date: 2015-08-12
Also published as: JP2015148195A; JP6297346B2

Abstract

A hermetic scroll compressor (1) includes a scroll compression mechanism (7) supported via a bearing member (6), a motor (8) connected to a drive shaft (11) supported with the bearing member (6), and a balance weight (34) provided on an end surface of a rotor (10) of the motor (8) along a periphery of the rotor (10), the end surface being on a side facing the bearing member (6). A length in an axial direction (L) of a journal bearing part (6A) pivotally supporting the drive shaft (11) in the bearing member (6) is set to 0.8 to 1.6 times a bearing diameter (D) and a flange part (34A) rising in the axial direction from a periphery region of the balance weight (34) is provided to overlap with a periphery side of an extended part in the axial direction (6B) of the journal bearing part (6A).

Description

Technical Field

The present invention relates to a hermetic scroll compressor that can decrease a ratio in which a lubricant oil (hereinafter also simply referred to oil) is discharged from a compressor into a refrigeration cycle side to circulate inside the cycle (= oil circulation rate (OC%)).

Background Art

In a hermetic scroll compressor, a bottom part of a hermetic container accommodating a compression mechanism and a motor is an oil storage part, and it is filled with a fixed amount of a lubricant oil. The lubricant oil is supplied to parts where lubrication is required, such as a bearing part with an oil supply pump and compulsively lubricates them. The lubricant oil is circulated inside the compressor by being discharged into the inside of the hermetic container after lubricating the parts where the lubrication is required to flow down to the oil storage part.
However, after lubricating the parts where the lubrication is required, the oil discharged therefrom comes in contact with a refrigerant gas while flowing down to the oil storage part, or is stirred up with a rotating body such as the motor and a balance weight provided on the motor, and some of the oil become an oil drop to be sucked into a compression chamber together with the refrigerant gas and discharged into a refrigeration cycle side together with a compressed gas. It is preferable that a restricted amount of the oil is supplied to the compression chamber in order to increase compression efficiency by sealing the compression chamber, but when an excess amount of the oil is supplied to flow out from the compressor to the refrigeration cycle side, there arises problems that the lubricant oil becomes insufficient on the compressor side to cause a failure, and in addition, a heat exchange is hindered on the refrigeration cycle side to decrease its performance.
It is quite difficult to control the outflow of the oil from the compressor to the refrigeration cycle side, that is to say the oil circulation rate (OC%), to allow it to have a restricted amount, and various proposals have been made conventionally. Patent Literatures 1, 2 disclose compressors in which in order that oil discharged from a journal bearing part of a bearing member that pivotally supports an end of a crank shaft is prevented from coming in contact with a refrigerant gas by being stirred up by rotation of a balance weight having a circular arc shape and provided on an end surface of a motor rotor and promptly flows down to an oil storage part of a hermetic container bottom part, the journal bearing part is extended downward in an axial direction and the balance weight provided on the end surface of the motor rotor overlaps with a periphery of the downward extended part of the journal bearing part, and a communication passage that allows the oil to flow down is provided on each of the balance weight and the motor rotor.

Citation List

Patent Literature

{PTL 1}

Japanese Unexamined Patent Application, Publication No. 2009-36136

{PTL 2}

Japanese Unexamined Patent Application, Publication No. 2010-121583

Summary of Invention

{Technical Problem

As described in Patent Literatures 1, 2, the journal bearing part that pivotally supports the crank shaft is extended in the axial direction and the downward extended part thereof overlaps with the balance weight, which are beneficial in order to prevent the oil discharged from the journal bearing part from being stirred up by the rotation of the balance weight and decrease an oil circulation rate (OC%). However, they are not always preferable because when a length in the axial direction of the journal bearing part is extended, a sliding loss in the bearing part increases, thereby decreasing compression efficiency.
Similarly, since a mass of the balance weight is determined based on a relation to an unbalanced load to be offset, if a size in the axial direction of the balance weight is set to be unnecessarily large in order to overlap with the journal bearing part, depending on it, it is necessary that a size in a circumferential direction of a circular arc is set to be short. This means that an effect of overlapping is decreased and thus it is not always preferable. Therefore, it is necessary to contrive a balance weight shape or the like.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a hermetic scroll compressor that can decrease an oil circulation rate (OC%) by preventing oil discharged from a journal bearing part from being stirred up by rotation of a balance weight while decreasing a sliding loss in the journal bearing part and improving efficiency.

Solution to Problem

A hermetic scroll compressor according to the present invention includes a scroll compression mechanism supported via a bearing member inside a hermetic container, a motor directly connected to a drive shaft pivotally supported with the bearing member, and a balance weight having a circular arc shape and provided on an end surface of a rotor of the motor along a periphery of the rotor, the end surface being on a side facing the bearing member. In the hermetic scroll compressor, a length in an axial direction L of a journal bearing part pivotally supporting the drive shaft in the bearing member is set to 0.8 to 1.6 times a bearing diameter D, and a flange part rising in the axial direction from a periphery region of the balance weight is provided to overlap with a periphery side of an extended part in the axial direction of the journal bearing part.
According to this configuration, since the length in the axial direction L of the journal bearing part pivotally supporting the drive shaft in the bearing member supporting the scroll compression mechanism is set to 0.8 to 1.6 times the bearing diameter D, a sliding loss due to the extension of the length in the axial direction of the journal bearing part can be decreased and the efficiency can be increased. At the same time, though the length in the axial direction L of the journal bearing part is set to be short, about 0.8 to 1.6 D, the flange part rising in the axial direction from the periphery region of the balance weight overlaps with the extended part in the axial direction of the journal bearing part, and thus oil having flowed out from the journal bearing part is allowed to flow out into the inner periphery side of the flange part of the balance weight rotating together with the rotor. Therefore, a phenomenon of stirring up the oil due to influence of rotation of the balance weight can be prevented, and increasing of an oil circulation rate (OC%) due to suction of the oil into the compression mechanism together with a refrigerant gas and discharge of the oil to the outside can be prevented. Further, since the flange part overlapping with the periphery of the journal bearing part rises in the axial direction from the periphery region of the balance weight, the length in the axial direction can be properly obtained while preventing influence on a mass and a size in the circumferential direction of the balance weight at a minimum. Accordingly, the sliding loss in the journal bearing part can be within an optimal range and efficiency of the scroll compressor can be improved, and in addition, the oil circulation rate (OC%) can be decreased, reliability of lubricant performance in the compressor can be improved, and heat exchange efficiency and performance on a refrigeration cycle side can be improved. Further, the shape of the balance weight can be optimal in order to obtain an effect of overlapping.
Further, in the above hermetic scroll compressor, the flange part may overlap with the extended part of the journal bearing part such that a gap in a radial direction is set to 1 to 2 mm, and overlap in the axial direction is set to at least 3 to 4 mm.
According to this configuration, interference between the flange part of the balance weight rotating at a high speed and the journal bearing part of the bearing member can be certainly prevented, and the phenomenon of stirring up the oil into a suction region over the flange part is sufficiently prevented by overlapping the flange part with the journal bearing part by at least 3 to 4 mm. Accordingly, the oil circulation rate (OC%) can be certainly decreased. Note that the balance weight normally has the semicircular arc shape, but a virtual barrier is formed on the lack part by the high speed rotation, and therefore the oil drop is prevented from being stirred up.
Further, in any of the above hermetic scroll compressors, a height in the axial direction of the flange part may be set to be higher than a height of a stator coil end of the motor.
According to this configuration, the flow of the refrigerant gas toward a center area over the stator coil end of the motor can be covered with the flange part of the balance weight and the oil having flowed out from the journal bearing part can be further prevented from coming in contact with the refrigerant gas, thereby decreasing the oil circulation rate (OC%) even further.
Further, in any of the above hermetic scroll compressors, at least one oil discharge hole passing through from an inner periphery side to a periphery side may be drilled on a base part of the flange part.
According to this configuration, the oil having flowed out from the journal bearing part and having flowed down to the upper end surface of the motor rotor can flow to a periphery side along its surface by centrifugal action to flow downward via an air gap between the rotor of the motor and a stator, and the oil having flowed out into the inner periphery side of the flange part can be discharged into the periphery side via the oil discharge hole drilled on the base part to flow downward from the air gap. Accordingly, the lubricant oil having flowed out from the journal bearing part can promptly return to an oil storage part and can be supplied for the next lubrication.
Further, in the above hermetic scroll compressor, a periphery end of the oil discharge hole may point toward the air gap between the rotor of the motor and the stator.
According to this configuration, the oil having flowed out to the inner periphery surface of the flange part can be directly guided to the air gap from the oil discharge hole drilled on the base part of the flange part, the periphery end of which points toward the air gap, and can flow downward. Accordingly, the lubricant oil can promptly return to the oil storage part without stagnating and can be supplied for the next lubrication.

Advantageous Effects of Invention

According to the present invention, a sliding loss due to an extension of a length in an axial direction of a journal bearing part can be decreased and efficiency can be increased. At the same time, oil having flowed out from the journal bearing part is allowed to flow out into an inner periphery side of a flange part of a balance weight rotating together with a rotor. Therefore, a phenomenon of stirring up the oil due to influence of rotation of the balance weight can be prevented, and increasing of an oil circulation rate (OC%) due to suction of an oil drop into a compression mechanism together with a refrigerant gas and discharge of the oil drop to the outside can be prevented. Further, the length in the axial direction can be properly obtained while preventing influence on a mass and a size in a circumferential direction of the balance weight at a minimum. Therefore, the sliding loss in the journal bearing part can be within an optimal range and efficiency of a scroll compressor can be improved, and in addition, the oil circulation rate (OC%) can be decreased, reliability of lubricant performance in the compressor can be improved, and heat exchange efficiency and performance on a refrigeration cycle side can be improved. Further, the shape of the balance weight can be optimal in order to obtain an effect of overlapping.

Brief Description of Drawings

Fig. 1
Fig. 1 is a longitudinal sectional view illustrating a hermetic scroll compressor according to a first embodiment of the present invention.
Figs. 2A and 2B
Fig. 2A is a plan view illustrating a motor rotor of the above hermetic scroll compressor, and Fig. 2B is a sectional view corresponding to a-a line of Fig. 2A.
Figs. 3A and 3B
Fig. 3A is a plan view illustrating a motor rotor according to a second embodiment of the present invention, and Fig. 3B is a sectional view corresponding to b-b line of Fig. 3A.

Description of Embodiments

With reference to the drawings, hereinafter, description will be given of embodiments of the present invention.

First embodiment

With reference to Fig. 1 and Figs. 2A and 2B, hereinafter, description will be given of the first embodiment of the present invention.
Fig. 1 is a longitudinal sectional view illustrating a hermetic scroll compressor according to a first embodiment of the present invention, Fig. 2A is a plan view illustrating a motor rotor of the hermetic scroll compressor, and Fig. 2B is a sectional view corresponding to a-a line of Fig. 2A.
The hermetic scroll compressor 1 includes a hermetic housing (hermetic container) 2 having a vertically long cylindrical shape, a bottom part of which is sealed with a lower cover.
An upper part of the hermetic housing 2 is sealed with a discharge cover 3 and an upper cover 4, and a discharge chamber 5 into which a compressed high pressure gas is discharged is formed between the discharge cover 3 and the upper cover 4. Inside the hermetic housing 2, an upper bearing member 6 is fixedly installed on an upper region, a scroll compression mechanism 7 is incorporated via the upper bearing member 6, and a motor 8 including a stator 9 and a rotor 10 is installed on a lower region. The motor 8 is incorporated with the stator 9 fixedly installed on the hermetic housing 2, and a drive shaft (crank shaft) 11 is fixed to the rotor 10.
There is provided a crank pin 12 having a shaft center eccentric by a predetermined distance on an upper end of the drive shaft 11. The crank pin 12 is connected to the scroll compression mechanism 7, so that the scroll compression mechanism 7 can be driven with the motor 8. In the drive shaft 11, an upper end part is rotatably and pivotally supported with a journal bearing part 6A of the upper bearing member 6, and a lower end part is rotatably supported with a journal lower bearing 13 provided on the lower region of the hermetic housing 2.
A displacement type oil supply pump 14 is provided between the journal lower bearing 13 and the lower end part of the crank shaft 11, and a lubricant oil 32 stored in an oil storage part 15 formed on the bottom part of the hermetic housing 2 is sucked via a suction pipe 16 and discharged into an oil supply hole 17 drilled in an axial direction inside the crank shaft 11. The lubricant oil 32 can be supplied to parts where lubrication is required, such as the upper bearing member 6, the scroll compression mechanism 7, and the journal lower bearing 13 via the oil supply hole 17.
The upper bearing member 6 is one of parts configuring the scroll compression mechanism 7, and the scroll compression mechanism 7 includes a fixed scroll 18 fixedly installed on the upper bearing member 6, a turning scroll 19 slidably supported with a thrust bearing part 6C of the upper bearing member 6 and forming a compression chamber 20 by meshing with the fixed scroll 18, a rotation prevention mechanism 21 such as an Oldham ring interposed between the upper bearing member 6 and the turning scroll 19 and preventing rotation of the turning scroll 19 and permitting its revolution turning movement, and a drive bush 22 and a turning bearing 23 provided between the crank pin 12 of the crank shaft 11 and a bearing boss 19A provided on a back of the turning scroll 19 and transmitting rotating force of the crank shaft 11 to the turning scroll 19. The scroll compression mechanism 7 is installed on the upper bearing member 6 in a state that an end plate center part of the fixed scroll 18 is connected to the discharge cover 3.
As is widely known, the fixed scroll 18 includes an end plate and a scroll wrap vertically installed on the end plate, a discharge port 24 is provided on a center part of the end plate, and a tip seal (not illustrated) is installed on a wrap tooth edge surface of the scroll wrap. Similarly, the turning scroll 19 includes an end plate and a scroll wrap vertically installed on the end plate, the bearing boss 19A is provided on the back of the end plate, and a tip seal (not illustrated) is installed on a wrap tooth edge surface of the scroll wrap.
The scroll compression mechanism 7 sucks a refrigerant gas having been sucked into the inside of the hermetic housing 2 via a suction piping 25 opening at a position facing a stator coil end 9A of the stator 9 into the inside of the compression chamber 20 from a suction port 26 provided inside the hermetic housing 2, and compresses it to allow it to have a high temperature and pressure. The compressed gas is discharged into the discharge chamber 5 via the discharge port 24 provided on the center part of the fixed scroll 18 and a discharge valve 27 provided on the discharge cover 3, and further is sent to a refrigeration cycle connected to the compressor via a discharge piping 28 connected to the discharge chamber 5.
Meanwhile, the lubricant oil 32 having been supplied to the drive bush 22 and the turning bearing 23 from an end part of the crank pin 12 via the oil supply hole 17 with the oil supply pump 14 and lubricated them is discharged into a motor upper space (suction region) inside the hermetic housing 2 via a discharge oil hole 29 provided on the upper bearing member 6, and flows down to the oil storage part 15 of the bottom part of the hermetic housing 2 via an oil guide 30 and an oil passage 31 provided on a periphery of the motor stator 9.
Further, in the scroll compression mechanism 7, the turning scroll 19 performs the revolution turning movement around the shaft center of the drive shaft (crank shaft) 11 with the eccentric amount of the crank pin 12 as its radius, and therefore, due to its centrifugal force, an unbalanced load is applied to the drive shaft 11. In order to offset the unbalanced load, balance weights 33, 34 are provided integrally with the drive bush 22 and the motor rotor 10, respectively. The balance weights 33, 34 each have a semicircular arc shape, and the balance weight 33 is integrally coupled to a lower end part of the drive bush 22 and the balance weight 34 is fixedly installed on an upper end surface of the motor rotor 10, the upper end surface facing the upper bearing member 6, within a range that slightly exceeds 180 degrees along a periphery of the upper end surface with bolts 35 or the like, as illustrated in Figs. 2A and 2B.
Further, in this embodiment, in order that the lubricant oil 32 having been supplied with the oil supply pump 14 and lubricated the journal bearing part 6A pivotally supporting the upper end part of the drive shaft 11 and then flowed out from the lower end part of the journal bearing part 6A is prevented from being sucked into the compression chamber 20 together with the refrigerant gas by being stirred up with the balance weight 34 and the like provided on the upper end surface of the motor rotor 10 and being circulated on the refrigeration cycle side together with the compressed gas, and thus an oil circulation rate (OC%) is prevented from increasing, the balance weight 34 provided on the upper end surface of the motor rotor 10 overlaps in the axial direction with a periphery part of an extended part in the axial direction 6B of the journal bearing part 6A.
In this case, if a length in the axial direction L of the journal bearing part 6A is set to be unnecessarily long in order to overlap the extended part in the axial direction 6B of the journal bearing part 6A with the balance weight 34, a sliding loss in the journal bearing part 6A increases, thereby decreasing efficiency. Therefore, assuming that the length in the axial direction of the journal bearing part 6A is L, and a bearing diameter of the journal bearing part 6A is D, the length in the axial direction L is set to within a range of 0.8 to 1.6 times the bearing diameter D, so that bearing performance is certainly obtained and the sliding loss in the journal bearing part 6A is within an optimal range.
Further, as to the balance weight 34, if a size in the axial direction is set to be unnecessarily large, it is necessary that a size in a circumferential direction of the circular arc shape is set to be reduced in order to have a predetermined mass. This means that an effect of overlapping is decreased and thus it is not preferable. Therefore, as illustrated in Figs. 2A and 2B, a flange part 34A, a thickness of which is set to be thin, rises in the axial direction from a periphery region of the balance weight 34 having the semicircular arc shape, and the flange part 34A overlaps with the periphery of the extended part in the axial direction 6B of the journal bearing part 6A.
The flange part 34A overlaps with the extended part in the axial direction 6B of the journal bearing part 6A such that a gap in a radial direction S is set to 1 to 2 mm in order that interference between the flange part 34A and the periphery of the journal bearing part 6A is certainly prevented, and an overlap amount in the axial direction W is set to at least 3 to 4 mm in order that the oil having flowed out from the journal bearing part 6A is prevented from being stirred up into the suction region over the flange part 34A. Further, a height in the axial direction of the flange part 34A is set to be higher than a height of the stator coil end 9A of the motor 8.
With the configuration described above, the following operation effects can be obtained according to this embodiment.
In the above hermetic scroll compressor 1, as is widely known, the compression chamber 20 formed between a pair of the fixed scroll 18 and the turning scroll 19 is formed such that the scroll wraps of the pair of the fixed scroll 18 and the turning scroll 19 face each other and mesh with each other with their phases shifted by 180 degrees.
When the hermetic scroll compressor 1 is driven with the motor 8, the refrigerant gas having a low pressure and having been sucked into the inside of the hermetic housing 2 via the suction piping 25 is confined inside the compression chamber 20 by being sucked via the suction port 26. The compression chamber 20 is moved in a sealed state while reducing capacity from a periphery position to a center position by being accompanied with the revolution turning movement of the turning scroll 19, so that it performs compression operation and compresses the refrigerant gas to allow it to have a high pressure.
During this period, the lubricant oil 32 stored in the oil storage part 15 of the hermetic housing 2 is supplied to the inside of the bearing boss 19A from the end of the crank pin 12 via the oil supply pump 14 and the oil supply hole 17 inside the drive shaft 11 to lubricate the drive bush 22, the turning bearing 23, the thrust bearing part 6C, the journal bearing part 6A, the journal lower bearing 13 and the like, and some of the lubricant oil 32 is sucked into the inside of the compression chamber 20 together with the refrigerant gas to be supplied to the seal of the compression chamber 20. The lubricant oil 32 having been supplied to the parts where the lubrication is required and lubricated them is discharged into the inside of the hermetic housing 2 from the discharge oil hole 29 provided on the upper bearing member 6, and flows down to the oil storage part 15 via the oil guide 30 and the oil passage 31 without coming in contact with the refrigerant gas as much as possible.
Meanwhile, though the oil having lubricated the journal bearing part 6A flows out from its lower end part to the upper space of the motor 8, in order that the oil having flowed out from the journal bearing part 6A is prevented from being circulated on the refrigeration cycle side together with the compressed gas by being stirred up due to the influence of the rotation of the balance weight 34 provided on the upper end surface of the rotor 10 of the motor 8 to be sucked into the compression chamber 20 together with the refrigerant gas, and thus the oil circulation rate (OC%) is prevented from increasing, this embodiment adopts the configuration in which the extended part in the axial direction 6B of the journal bearing part 6A overlaps in the axial direction with the balance weight 34, so that the outflow oil from the journal bearing part 6A is prevented from being stirred up with the balance weight 34.
Further, in this embodiment, in order to adopt the configuration in which the extended part in the axial direction 6B of the journal bearing part 6A overlaps with the balance weight 34, assuming that the length in the axial direction of the journal bearing part 6A is L, and the bearing diameter of the journal bearing part 6A is D, the length in the axial direction L is set to 0.8 to 1.6 times the bearing diameter D, the flange part 34A rising in the axial direction from the periphery region of the balance weight 34 is provided on the balance weight 34, and the flange part 34A overlaps with the periphery side of the extended part in the axial direction 6B of the journal bearing part 6A.
In this manner, the length in the axial direction L of the journal bearing part 6A pivotally supporting the drive shaft 11 in the upper bearing member 6 is set to 0.8 to 1.6 times the bearing diameter D, so that the sliding loss due to the extension of the length in the axial direction of the journal bearing part 6A can be decreased and the efficiency can be increased. At the same time, though the length in the axial direction L of the journal bearing part 6A is set to be short, the flange part 34A rising in the axial direction from the periphery region of the balance weight 34 overlaps with the extended part in the axial direction 6B, and thus the oil after lubricating flowing out from the journal bearing part 6A can be allowed to flow out into the inner side of the flange part 34A, the phenomenon of stirring up the oil due to the influence of the rotation of the balance weight 34 can be prevented, and the increasing of the oil circulation rate (OC%) due to the suction of the oil drop into the scroll compression mechanism 7 together with the refrigerant gas can be prevented.
Further, since the flange part 34A overlapping with the periphery of the journal bearing part 6A rises in the axial direction from the periphery region of the balance weight 34, the length in the axial direction can be properly obtained while preventing the influence on the mass and the size in the circumferential direction of the balance weight 34 at a minimum.
In this manner, according to this embodiment, the sliding loss in the journal bearing part 6A can be within the optimal range and the efficiency of the hermetic scroll compressor 1 can be improved, and in addition, the oil circulation rate (OC%) can be decreased, reliability of the lubricant performance in the compressor 1 can be improved, and heat exchange efficiency and performance on the refrigeration cycle side can be improved. Further, the shape of the balance weight 34 can be optimal in order to obtain the effect of overlapping.
Further, since the flange part 34A overlaps with the extended part in the axial direction 6B of the journal bearing part 6A such that the gap in the radial direction is set to 1 to 2 mm and the overlap in the axial direction is set to at least 3 to 4 mm, the interference between the flange part 34A of the balance weight 34 rotating at a high speed and the journal bearing part 6A of the bearing member 6 can be certainly prevented, and the phenomenon of stirring up the oil into the suction region over the flange part 34A can be sufficiently prevented by overlapping the flange part 34A with the journal bearing part 6A by at least 3 to 4 mm. Therefore, the oil circulation rate (OC%) can be certainly decreased. Note that the balance weight 34 normally has the semicircular arc shape, but a virtual barrier is formed on the lack part by the high speed rotation, and therefore the oil drop is prevented from being stirred up.
Further, in this embodiment, the height in the axial direction of the flange part 34A is set to be higher than the height of the stator coil end 9A of the motor 8. Therefore, the flow of the refrigerant gas toward a center area over the stator coil end 9A of the motor 8 can be covered with the flange part 34A of the balance weight 34 and the oil having flowed out from the journal bearing part 6A can be further prevented from coming in contact with the refrigerant gas, thereby decreasing the oil circulation rate (OC%) even further.

Second embodiment

Next, with reference to Figs. 3A and 3B, description will be given of the second embodiment of the present invention.
In this embodiment, a configuration of a balance weight 34 is partly different from that in the above first embodiment. The other points are the same as those in the first embodiment, and description thereof is omitted.
In this embodiment, as illustrated in Figs. 3A and 3B, an oil discharge hole 36 passing through from an inner periphery side to a periphery side is provided on at least one part in a circumferential direction of a flange part 34A of the balance weight 34, and a periphery end of the oil discharge hole 36 points toward an air gap 37 (see Fig. 1) between a stator 9 of a motor 8 and a rotor 10.
In this manner, the at least one oil discharge hole 36 passing through from the inner periphery side to the periphery side is drilled on a base part of the flange part 34A, so that oil having flowed out from a journal bearing part 6A and having flowed down to an upper end surface of the motor rotor 10 can flow to a periphery side along its surface by centrifugal action to flow downward via the air gap 37 between the stator 9 of the motor 8 and the rotor 10, and the oil having flowed out into the inner periphery side of the flange part 34A can be discharged into the periphery side via the oil discharge hole 36 drilled on the base part to flow downward from the air gap 37. Thereby, the lubricant oil 32 having flowed out from the journal bearing part 6A can promptly return to the oil storage part 15 and can be supplied for the next lubrication.
Further, since the periphery end of the oil discharge hole 36 points toward the air gap 37 between the stator 9 and the rotor 10, the lubricant oil 32 having flowed out to the inner periphery side of the flange part 34A can be directly guided to the air gap 37 from the oil discharge hole 36 drilled on the base part of the flange part 34A, the periphery end of which points toward the air gap 37, and can flow downward. Therefore, the lubricant oil 32 can promptly return to the oil storage part 15 without stagnating and can be supplied for the next lubrication.
Note that the present invention is not limited to the invention according to the embodiments described above and modifications can be made appropriately without departing from the scope of the present invention. For example, in the above embodiments, the description is given of the example in which the present invention is applied to the hermetic scroll compressor 1 of the type in which the refrigerant gas having the low pressure is sucked into the inside of the hermetic housing 2 and the inside of the housing 2 is in the low pressure atmosphere, but it goes without saying that the present invention can also be applied to a hermetic scroll compressor of a high pressure housing type in which a low pressure refrigerant gas is directly sucked into a compression chamber and a high pressure gas compressed with the scroll compression mechanism 7 is discharged into the inside of the hermetic housing 2.

Reference Signs List

1: Hermetic scroll compressor
2: Hermetic housing (hermetic container)
6: Upper bearing member
6A: Journal bearing part
6B: Extended part in axial direction
7: Scroll compression mechanism
8: Motor
9: Stator
9A: Stator coil end
10: Rotor
11: Drive shaft (crank shaft)
34: Balance weight
34A: Flange part
36: Oil discharge hole
37: Air gap
L: Length in axial direction
D: Bearing diameter
S: Gap in radial direction
W: Overlap amount

Claims

A hermetic scroll compressor (1) characterized in that it comprises:
a scroll compression mechanism (7) supported via a bearing member (6) inside a hermetic container (2);

a motor (8) directly connected to a drive shaft (11) pivotally supported with the bearing member (6); and

a balance weight (34) having a circular arc shape and provided on an end surface of a rotor (10) of the motor (8) along a periphery of the rotor (10), the end surface being on a side facing the bearing member (6), wherein

a length in an axial direction L of a journal bearing part (6A) pivotally supporting the drive shaft (11) in the bearing member (6) is set to 0.8 to 1.6 times a bearing diameter D, and

a flange part (34A) rising in the axial direction from a periphery region of the balance weight (34) is provided to overlap with a periphery side of an extended part in the axial direction (6B) of the journal bearing part (6A).
The hermetic scroll compressor (1) according to claim 1, wherein the flange part (34A) overlaps with the extended part (6B) of the journal bearing part (6A) such that a gap in a radial direction is set to 1 to 2 mm, and overlap in the axial direction is set to at least 3 to 4 mm.
The hermetic scroll compressor (1) according to claim 1 or 2, wherein a height in the axial direction of the flange part (34A) is set to be higher than a height of a stator coil end (9A) of the motor (8).
The hermetic scroll compressor (1) according to any of claims 1 to 3, wherein at least one oil discharge hole (36) passing through from an inner periphery side to a periphery side is drilled on a base part of the flange part (34A).
The hermetic scroll compressor (1) according to claim 4, wherein a periphery end of the oil discharge hole (36) points toward an air gap (37) between the rotor (10) of the motor (8) and a stator (9).